IN DEFENSE OF COLD WATER

A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 3: Heat and cold tolerance during exercise

In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.

Prevention and Management of Physical and Social Environment Risk Factors for Sports-Related Injuries

An understanding of the environmental factors that contribute to injury risk will allow for the optimization of athletic performance and minimize morbidity. The purpose of this review is to discuss the physical and social environments of sport that affect injury risk, and to review the strategies that sports medicine professionals (eg, clinicians, certified athletic trainers) can implement to prevent injury. Searches using the PubMed, Cochrane, and Google Scholar databases were used to identify injury risk factors pertaining to the physical and social environment of athletics. Physical environmental risk factors identified include weather, air quality, playing surface, and the presence of sports medicine professionals. Social environmental factors include parents, teammates, coaches, media, policy/legislation, and sports medicine professionals. Sports medicine professionals seeking effective prevention and care strategies will benefit from (1) education about the physical and social environmental risk factors that place athletes at risk for injury and (2) a holistic approach that recognizes that physical and social factors are as important as individual risk factors in determining injury risk.